TURBULENCE IN THE SUB-ALFVENIC SOLAR WIND DRIVEN BY REFLECTION OF LOW-FREQUENCY ALFVEN WAVES

Journal Article · Mon Jul 20 04:00:00 EDT 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/700/1/L39; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21313882

Verdini, A ^[1]; Velli, M ^[2]

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1. Observatoire Royale de Belgique, 3 Avenue Circulaire, 1180, Bruxelles E-mail (Belgium)
2. Dip. di Astronomia e Scienza dello Spazio, Univ. di Firenze, Largo E. Fermi 3, 50125 Firenze (Italy)

We study the formation and evolution of a turbulent spectrum of Alfven waves driven by reflection off the solar wind density gradients, starting from the coronal base up to 17 solar radii, well beyond the Alfvenic critical point. The background solar wind is assigned and two-dimensional shell models are used to describe nonlinear interactions. We find that the turbulent spectra are influenced by the nature of the reflected waves. Close to the base, these give rise to a flatter and steeper spectrum for the outgoing and reflected waves, respectively. At higher heliocentric distance both spectra evolve toward an asymptotic Kolmogorov spectrum. The turbulent dissipation is found to account for at least half of the heating required to sustain the background imposed solar wind and its shape is found to be determined by the reflection-determined turbulent heating below 1.5 solar radii. Therefore, reflection and reflection-driven turbulence are shown to play a key role in the acceleration of the fast solar wind and origin of the turbulent spectrum found at 0.3 AU in the heliosphere.

• OSTI ID: 21313882
• Journal Information: Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 1 Vol. 700; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ALFVEN WAVES
ASYMPTOTIC SOLUTIONS
HELIOSPHERE
MAGNETOHYDRODYNAMICS
NONLINEAR PROBLEMS
REFLECTION
SHELL MODELS
SOLAR WIND
SPECTRA
TURBULENCE
TURBULENT HEATING
TWO-DIMENSIONAL CALCULATIONS